Electric clock



June 9, 1925;

- A. B. HARJE znscnuc cLocx Filed March 15, 1922 TIEJ- n IO l2 I5 A J JJ Ab ta-5..

AUGUST, BENGTSSON HARJE,

1,541,138 PATENT OFFICE.

OF COPENHAGEN, DENMARK.

ELECTRIC CLOCK.

Application filed March 15, 1922.

To all whom it may concern:

Be it known that 1, AUGUST BENcTssoN HKRJE, a subject of the King of Sweden, whose residence is Copenhagen, in the Kingdom of Denmark, haveinvented certain new and useful Improvements in Electric Clocks, of which the following is a full, clear, and exact description. 1

My invention concerns clocks with electrically driven pendulum, and has for its object to reduce the current consumption to 4 a minimum and to simplify the clock. A

small galvanic element can be used, which, owing to the small consumption of current only needs renewal at long intervals,yearl or even longer.

, According to the invention, the contactmechanism through the action of which the oscillation of the pendulum periodically is accelerated, and the mechanism by means'of which the motion of the pendulum is transferred to the hands, are combined to form a single mechanism, being at the same time contact closing and motion transferring. The mechanism may be a pawl and ratchet wheel, or the like, which latter at the oscillation of the pendulum to the one side, is turned one or more teeth by means of the pawl, and simultaneous therewith the pawl forms a contact, thus closing a circuit serving to accelerate the motion of the pendulum electromagnetically. At the oscillation of the pendulum in the opposite direction the pawl may slide on the teeth of the Wheel without turning it, preferably with so slight a pressure against the teeth of the wheel that no real contact happens, thus making insulation of the contact faces superfluous.

One form of construction is by way of example diagrammatically shown on the drawing utilized in a clock with torsionpendulum. Figs. 1 and 2 show a side view and a plan view respectively. Figs. 3 and 4 show a detail and Fig. 5 shows a modification.

The torsion-pendulum 5 shown on the drawing has steel magnetsfi fastened across and able to be attracted by coils 7 when passing over and under them; or one of the coils may attract and the other-repel the magnets. The coils are in a circuit including a conductor 8 connected with a source of electromotive force 9, the latter being connected through the torsion spring of the pendulum inseries with a contactmechanism consisting of a pawl in the shape Serial No. 543,928.

of a lever 10 and a ratchet wheel 12 in the clockwork 13 the latter being connected by a conductor 8 with the coils. The lever is mounted on an arm 11 on the torsion-pendulum and during the oscillation of the same, it engages the ratchet wheel.

When the torsion-pendulum turns in the direction shown by an arrow 14 in Fig. 3, the pawl will touch one of the teeth 15 of wheel 12 and as the pawl by means of an arm 16 is stopped in the position shown it will turn the wheel and the hands. Owing to the contact between the pawl and the ratchet wheel, the circuit 8 is closed, the. current passing from the pendulum to the clockwork and further on to the coils, thus giving the pendulum a turning-impulse. When the pawl passes the position shown in Fig. 3, the circuit is broken.

As the voltage and force of the current is small'and as the self-induction by means of known arrangements can be very reduced, no sparks of any importance are formed in the breaking moment. Consequently the contact-faces are maintained clean. Y

When the pendulum turns in the opposite direction, or the direction of the arrow 17 in Fig. 4, the pawl without any contact or only at the very slightest one, passes under the tooth 15 on which it has just acted according to Fig. 3; then it touches the following tooth but now the pawl will swing as shown by the arrows 18, without turning the wheel, and owing to the lightness of the pawl the pressure between it and the wheel is too light to form an electric contact of any importance. In connection with the wheel 12 or its shaft may be arranged a mass of some suitable size, insuring to a certain extent the reduction of the time of contact and to keep the amplitudes of the pendulum constant.

The ratchet wheel shown in Figs. 3 and 4 can at each oscillation of the pendulum only be turned one tooth forward. The modification shown in Fig. 5 is intended to obtain the same result for all forms of ratchet wheels, so as to ensure, that the wheel only turns one tooth or a certain number of teeth each time, even when the pawl or the like beforehand would be able to turn the wheel several teeth for each oscillation of the pendulum. The modification consists in a particular guiding member 19 having a recess, a notch or the like 20. The mem her 19 prevents the engagement of the pawl 10 during'a'ce'rtain part of the oscillation. Only when passing the notched portion 20, can the pawl actupon a tooth 15, and turn the wheel one tooth or a definitef-number of teeth forward, after which it again is disengaged by the guiding member. lV'hen necessary the guiding member may be insulated.

Preferably the impulse should be given when the pendulum has its maximum speed, i. e., in the middle of the oscillation. The use of atorsiOn pendulum orother similar pendulum with a-slow oscillation, has the advantage, that there is comparatively a long time between each impulse, so that :any over-exertion of the element is avoided, the more so as only very little energy is required for each impulse.

Preferably the-two magnets 6 'forman astatic magnet. This magnet and the coils form a closed magnetic circuit, but in order to reducethe self-induction no iron is employed in the coils.

I do mot confine myself to the details shown; these may be altered in many ways, according to thekind and performance of the clock and pendulum.

I claim: v 1. In an electric clock,-a'torsion-pendulum including a flexible member and abody suspended from the lower end thereof, a clockwork mechanism including a toothed wheel, a pivoted member carried by the pendulum body engageable by the teeth of said wheel for intermittently rotating the latter, means for limiting the swinging movement of said pivoted member in one direction, electro-magnetic means for pcriodically accelerating-the movement of said pendulum, said toothed wheel and pivoted member constituting a contact device for controlling said electro-magnetic means, and said pendulum being arranged to rotate in a given direction before and after contact of said contact device.

2. In an electric clock as claimed in claim 1, characterized by the provisionof means for guiding the movement of said pivoted member.

In an electric clock, a rotating pendulum including a flexible member and a-body suspended from the lower end thereof, a support carried by said pendulum body,

electric magnetic means associated with said pendulum for periodicallyaccelerating the movement of the latter, a clock work mech anism including a toothedwheel, a member pivotally mounted on said support andarranged to engage the teeth of said wheel and impart movement. of the pendulum whereby movement of the latter is transmitted to the clock-work mechanism,= said toothed wheel and pivoted member constituting a contact device for controlling the said electro-magnetlc means.

In witness whereof I subscribe my signatnre.

AUGUST BENGT SSON HKRJ E. 

